Production of alkenyl aromatic hydrocarbons



United States Patent 3,20,043 PRUDUCTION 0F ALKENYL ARQMATICHYDROCARBONS Norbert F. Cywinski and Harold J. Hepp, Bartlesville,

Okla assignors to Phillips Petroleum Company, a corporation of DelawareNo Drawing. Filed Mar. 8, 1963, Ser. No. 263,751 12 Claims. (Cl. 260668)This is a continuation-in-part application of our copending applicationhaving Serial No. 120,149, filed June 28, 1961, now abandoned.

This invention relates to the formation of alkenyl aromatic hydrocarbonsfrom hydrocarbon-substituted aromatics. In accordance with anotheraspect, this invention relates to a novel process involving acondensation reaction for the production of alkenyl aromatichydrocarbons or aryl-substituted olefins from hydrocarbon-substitutedaromatics and a l-acetylene. In a further aspect, this invention relatesto the reaction of toluene and acetylene to yield allylbenzene.

Various processes are known for the production of substituted aromatichydrocarbons from lower molecular weight materials. Some of these knownprocesses employ catalysts while others are purely thermal. However,many of the known processes have various disadvantages for one reason oranother. For example, some of the known processes require hightemperatures, others requires expensive catalysts, while still othersrequire expensive and difiicult to produce reactants. Thus, it can besafely stated that there is still considerable room for improvement inthe production of these materials, especially with respect to theprovision of a process whereby readily available reactants can be usedfor the production of valuable aromatic hydrocarbon products.

The present invention relates to a novel process for the production ofalkenyl aromatic hydrocarbons by the condensation ofhydrocarbon-substituted aromatics and an acetylene.

Accordingly, an object of this invention is to provide a novel processfor the production of alkenyl aromatic hydrocarbons.

Another object of this invention is to provide a process for thecondensation of hydrocarbon-substituted aromatic hydrocarbons and anacetylene.

It is a further object of this invention to provide a free radicalinitiated process for producing alkenyl aromatics by condensation of al-acetylene and hydrocarbonsubstituted aromatics.

Another object of this invention is to provide a process for theproduction of allylbenzene.

Other objects, aspects, as well as the several advantages of thisinvention will be apparent to those skilled in the art upon a furtherstudy of the specification and the ap pended claims.

According to the invention set forth in said copending application, Weprovide a novel process for the production of alkenyl aromatichydrocarbons which comprises contacting a methyl-substituted aromatichydrocarbon with an acetylene under suitable reaction conditions oftemperature and pressure in the presence of a free radical initiator,and recovering the alkenyl aromatic product thus produced.

It has now been found that substituted aromatic hydrocarbons having asaturated hydrocarbon side chain of 1 to 10, or more, carbon atoms canbe reacted with 1- acetylenes in the presence of a free radicalinitiator to form long chain aryl-substituted monoolefin hydrocarbonproducts. It has been further found that aryl-substituted l-olefins canbe produced from acetylene and hydrocarbon-substituted aromatichydrocarbons.

The substituted aromatic hydrocarbon reactants that now can be employedaccording to the invention have at least 7 carbon atoms per molecule andinclude monoand poly-hydrocarbon substituted benzenes as Well as monoandpoly-hydrocarbon substituted polycyclic aromatics such as naphthalene,anthracene, chrysene, pyrene,

Although there is no critical upper limit and the like. for themolecular weight of the substituted aromatic reactants, generallysubstituted aromatics containing from 7 to about 24 carbon atoms permolecule are used. In general, the aromatic hydrocarbon reactants of theinvention can be defined as compounds having the formula Ar-CH R whereinAr is selected from alkylsubstituted and unsubstituted monoandpolycyclic aromatic hydrocarbons and R is selected from hydrogen andsaturated hydrocarbon radicals having from 1 to 10, inclusive, carbonatoms. The hydrocarbon radicals that can be used include specificallysaturated aliphatic, saturated cycloaliphatic, and aromatic radicals.

Representative examples of suitable substituted aromatic hydrocarbonsthat can be employed include toluene, ortho-, metaand para-xylenes,ethyl-benzene, npropylbenzene, butylbenzene, octylbenzene, decylbenzene,l,2,3-trimethylbenzene, 1,2,4-trimethylbenzene, 1, 3 ,5-trimethylbenzene, LZ-diethylbenZene, 1,2-dipropylbenzene,l-methylnaphthalene, 2-ethylnaphthalene, 1,4- dipropylnaphthalene,1ethyl-8-methylnaphthalene, 1,2, B-trimethylnaphthalene,1,2,4-trimethylnaphthalene, l, 6,S-trimethylnaphthalene,l-methylanthracene, 2-ethylanthracene, 1,10-diethylanthracene,1,2-dipropylanthracene, l-methylphenanthrene, 2-ethylphenanthrene, 1,2-dimethylphenanthrene, 1,3-diethylphenanthrene, l-methylchrysene,Z-ethylchrysene, 1,2-dirnethylchrysene, 1,3- diethylchrysene,l-methylpyrene, Z-ethylpyrene, 1,3- diethylpyrene, diphenylmethane,phenylcyclohexylmethane, and the like. It is to be understood that theabovementioned aromatic hydrocarbons are set forth only as examples ofthe compounds which can be used in the process of the invention.

The acetylene materials or compounds that can be employed according tothe invention are the l-acetylenes containing from 2 to 5 carbon atomsand include acetylene, 1-propyne, l-butyne, l-pen tyne, and3-methy1-lpentyne and mixtures thereof.

As indicated above, the condensation, reaction of the invention iscarried out in the presence of a free radical initiator. Suitableinitiators for furnishing free radicals are organic peroxy and azocompounds which have half lives in the range of 0.05 to 20 hours atreaction conditions, actinic radiation, gamma radiation, and metalalkyls of the metals of Groups IIb and Nb of the Periodic System(Mendelyeev).

Representative examples of suitable organic peroxy and azo free radicalinitiators include di-tert-butyl peroxide, tert-butyl hydroperoxide,benzoyl peroxide, azobisisobutyronitrile, tert-butylbenzenehydroperoxide, dicumyl peroxide, and the like.

Also, according to the invention, actinic rays such as ultraviolet rayswhich have a photochemical efiect can be employed in conjunction withthe organic peroxy and azo free radical initiators, in particular, toincrease the reaction rate and reduce the temperature and/or timerequirement for equivalent conversion. Ultraviolet, for example, assistsin starting free radical formation.

When either actinic or gamma radiation is used, the total dosage ofradiation to which the reaction mixture is exposed is in the range of 10to 10 roentgens. The rate of exposure to the radiation is generally atthe rate of 10 to 10 roentgens per hour until said reaction mixture hasreceived said total dosage, although higher or lower rates can beemployed.

Numerous sources of gamma rays for irradiation of the hydrocarbons areavailable. Such sources as spent fuel elements from nuclear reactor arequite satisfactory and may b very economically used, for these areordinarily allowed only to deteriorate in activity and then reprocessedfor recovery of the fissionable material. By using these spent fuelelements in this process, the radiant energy available a gamma rays isput to use in producing valuable alkenyl aromatics. Other sources ofgamma rays, of course, may be utilized, for example, radioactivematerials such as cobalt-60 and similar radioactive materials. Any othersuitable source of gamma radiation can be used.

It is also Within the scope of the invention to employ alkyls of themetals of Groups IIb and IVb of the Periodic System (Mendelyeev)including specifically zinc, cadmium, mercury, germanium, tin and leadas free radical initiators. Ordinarily the alkyl groups will containfrom 1 to 5, inclusive, carbon atoms, although longer chain alkyl groupscan be employed under some circumstances, and the alkyl groupssubstituted on each metal can be the same or different. Representativeexamples of suitable metal alkyls that can be used include dimethylzinc,dibutylzinc, diethylcadmium, dimethylmercury, dipropylmercury,diamylmercury, tetraethylgermanium, tetramethyltin, tetraethyllead, andthe like.

A discussion of the chemical'reactions of tetraethyllead, including itsuse as a free-radical initiator, can be found on pages 306-318 ofAdvances in Chemistry, No. 23, American Chemical Society, 1959. Ageneral discussion on metal alkyls as free radicals can be found in FreeRadicals, an Introduction, Trotman-Dickenson, Wiley, 1959.

Although the mechanism of the reaction involved in the present processis not completely understood, it most probably involves the followingreactions between toluene and acetylene, for example, for the productionof allyl benzene when a peroxide free-radical initiator is used:

However, the invention is not to be construed as limited by any theoryregarding the reaction mechanism. Broadly, the reactions can beexpressed as follows when a peroxide free radical initiator is used:

Ar-CH. CHECH Ar-CHCH=CH Thus, in carrying out our invention we react,for example, toluene with acetylene and obtain allylbenzene. Similarly,ethylbenzene upon reaction with acetylene yields 3-phenylbutene-1;ropylbenzene and acetylene yield 3-phenylpentene-1; l-ethylnaphthaleneand acetylene yield 3-naphthylbutene-1, and the like. It will beobserved that long chain aryl-substituted olefins are formed accordingto the invention by reacting hydrocarbon-substituted aromatics withacetylenes in the presence of a free radical initiator.

The reaction conditions under which the process of the present inventionproceeds can vary appreciably and will depend largely upon the reactantsand the initiator employed. Generally, temperatures ranging from about150 to about 700 F., or more, will be used in the reaction, thepreferred range being from about 200 to about 650 F.

The reaction pressure employed is snfiicient to maintain liquid phaseconditions and ordinarily will range from about 50 p.s.i.g. toapproximately 2000 p.s.i.g., preferably from about to about 1500p.s.i.g. The reaction or contact time will ordinarily range from about0.1 second to about 100 hours, preferably from about 1 second to 10hours. As indicated above, the use of ultraviolet light in conjunctionwith the free radical initiator increases the reaction rate and reducestemperature and/or time requirement for equivalent conversion.

The ratio of reactant and initiator employed according to the inventionwill vary appreciably. Generally, the mole ratio of acetylene materialto initiator will range from about 10021 to about 1:1, preferably fromabout 50:1 to 5:1. The mole ratio of substituted aromatic to acetylenematerial will range from about 100:1 to about 2:1, preferably from about50:1 to about 3:1.

The process of this invention can be effected in any suitable manner andcan comprise a batch, intermittent, or continuous type operation. Also,the process of this invention can be carried out in the absence orpresence of a non-reactive liquid diluent or solvent. When a batch typeoperation is used, for example, the substituted aromatic compound can becharged to a reactor (autoclave) first followed by the initiator and anacetylene. Since some of the substituted aromatic hydrocarbon reactantsof the invention are solid materials, it is preferred to dissolve suchmaterials in a suitable organic non-reactive solvent such as benzeneprior to charging same to the reaction zone. However, as indicatedabove, any of the known operative procedures can be employed in carryingout the process of the invention.

The usual precautions for handling acetylene under pressure should beobserved. Explosions can be prevented in handling acetylene underpressure by dilution with other gases (nitrogen, methane, etc.),operating with limited free space in the lines and vessels in whichacetylene is under pressure, and other means known in the art forhandling acetylene.

The reaction product obtained according to the present process containsunreacted materials, alkenyl aromatic hydrocarbon materials and higherboiling products. At the completion of the condensation reaction thetotal reaction mixture can be subjected to any suitable known separationprocedure such as distillation, extraction, etc., for recovery of thealkenyl aromatic hydrocarbon product.

It is desirable to keep the reaction system as free of chain terminatingcomponents as practicable since the condensation reaction appears to bea chain reaction once it is initiated. Such undesirable materialsinclude mercaptans, quinones, and the like. It is highly desirable,therefore, that the feed components or reactants be freed of thesematerials as well as other materials which may tend to inhibit thereaction. Any of the known means for removing such contaminants can beused. High feed purity with respect to these undesirable chainterminating components produces higher yields of product based on theinitiator.

The alkenyl aromatic hydrocarbon products produced in accordance withthe present invention are articles of commerce and have wide utility inthe chemical industry. Allyl benzene is very valuable in particular asan intermediate in many chemical processes. For example, allyl benzeneis readily isomerized to propenylbenzene by heating in the presence ofalcohol KOH. Propylbenzene can be polymerized to homopolymers andcopolymers, which are useful as coatings, castings, insulation,adhesives, fibers, etc. Also, a useful antioxidant for resins, dryingoils, etc. can be prepared from propenylbenzene by refluxing aniline,aniline hydrochloride and propenylbenzene together to form acondensation product and reacting this product with acetone to make2,2,4-trimethyl-6-(1- phenylisopropyl)-1,2-dihydroquin0line, which isthe antioxidant.

A better understanding of our invention will be obtained upon referenceto the following illustrative examples which are not intended, however,to be undulylimitative of the invention. Example I A run was carried outin which toluene was contacted with acetylene in the presence of'di-tert-butyl peroxide to form allylbenzene.

In a l-liter Magne Dash stirred autoclave, 500 ml. (430 grams, 4.67mole) of toluene and 100 ml. (78 grams, 0.53 mole) of di-t-butylperoxide were heated-28 hours at 257' F. using a pressure of 100 psi. ofacetylene. p.s.i.g.

The recovered product (517 grams) was washed with Water. Some pentanewas added at this point to aid in the phase separation. The organicphase was then dried over anhydrous potassium carbonate, 25 ml. ofn-decane was added, and the product was distilled through a Minnicalcolumn. Eighteen grams of distillate was collected in the range 302 to349 F. Analysis by gas chromatography indicated that this distillatecontained 5.6 grams of allylbenzene. Eighty-nine grams of heavy residueremained after distilling most of the allylbenzene and added n-decane.An infrared spectrum of the center cut of the distillate was identicalwith that of known allylbenzene.

Example II A run was carried out in which cumene was contacted withacetylene in the presence of di-tert-butyl peroxide.

No condensation products of cumene and acetylene were detected in theproduct.

Example 111 Another test was carried out in the same manner as ExampleII except for the temperature, which was 650 F. Again, no condensationproduct of cumene and acetylenewas detected.

Example IV A feed mixture containing 800 ml. (6.54 moles) ofethylbenzene, 1.8 ml. (0.0092 mole) of tetraethyllead, and 2 ml. ofnormal pentane (as a reference standard for subsequent acetyleneanalysis) was pressured to 105 p.s.i.g. with nitrogen, and acetylene wasadded to a total pressure of 130 p.s.i.g. Analysis showed thatapproximately 2 weight percent of acetylene (0.7 mole) was present inthe liquid feed. The mixed feed was pumped through a heated tubularreactor at a temperature of 330 C. (626 F.), a pressure of 1000p.s.i.g., and a liquid hourly space velocity of 1.0.

Analysis of the product by gas chromatography indicated that 5.3 grams(0.04 mole) of 3-penylbutene-l was formed. Product identity was furtherconfirmed by infrared and mass spectroscopy.

As will be evident to those skilled in the art, many variations andmodifications of this invention can be practiced in view of theforegoing disclosure. Such variations and modifications are clearlybelieved to come within the spirit and scope of the invention.

We claim:

1. A process for the production of alkenyl aromatics which comprisescontacting at elevated temperatures a methyl-substituted aromatic.hydrocarbon wherein the aromatic hydrocarbon is selected fromalkyl-substituted and unsubstituted monoand polycyclic aromatichydrocarbons, said methyl-substituted aromatic hydrocarbon containingfrom 7 to 24, inclusive, total carbon atoms with at least one acetyenicmaterial selected from the group consisting of acetylene, l-propyne,l-butyne, 1- pentyne, and 3-methyl-l-pentyne, in the presence of achemical free radical [initiator selected from the group consisting oforganic peroxy compounds which have half lives in the range of 0.05 to20 hours at reaction conditions, organic azo compounds which have halflives in Nitrogen was added to a total pressure of 250 6 the range of.0.05 to 20 hours at reaction conditions, and metal alkyls of the metalsof Groups IIb and Nb of the Periodic System. (Mendelyeev), andrecovering said alkenyl aromatic thus, produced.

2. A process for. the production of allyl aromatics which comprisescontacting a methyl-substituted aromatic hydrocarbon wherein thearomatic hydrocarbon is selectcd from alkyl-substituted andunsubstituted monoand polycyclic aromatic hydrocarbons, saidmethyl-substituted aromatic hydrocarbon containing from 7 to 24,inclusive, total carbon atoms with acetylene at a temperature rangingfrom about 150 to about 700 F. in the presence of an. organic. peroxyfreeradial initiator which havehalf lives, in the range of.0.05 to 20hoursatreaction conditions, the mole ratio of acetylene to initiator.ranging from about :1 to about 1:1, and recovering said allylaromaticthus produced.

3. A process for the production of allylbenzene which comprises;contacting toluene, with acetylene at a temperature ranging from aboutto about 700 F. in the presence of a, di-tert-butyl peroxide asthe freeradical initiator.

4. A process for the production of allylbenzene which comprises,contacting toluene with acetylene at a temperature ranging from about200' to about 650 F. in the presence of di-tert-butyl. peroxide, themole ratio of acetylene to peroxide from about 50:1 to about 5:1 and theratio of toluene-to acetylene ranging from about 50:1 to about 3:1, andrecovering allylbenzene as a product of the process.

5. A process for the production of alkenyl aromatic hydrocarbons whichcomprises contacting (1') a hydrocarbon-substituted aromatic hydrocarbonof the formula Ar-CH --R wherein R is selected from the group consisLing of hydrogen and saturated hydrocarbon radicals of- 1 to 10,inclusive, carbon atoms and Ar is an aromatic nucleus selected fromthegroup consisting of alkyl-substituted and unsubstituted monoandpolycyclic aromatichydrocarbon nuclei, said hydrocarbon-substitutedaromatic hydrocarbon containing from 7 to 24, inclusive, total carbonatoms, with (2) at least one acetylenic material selected from the groupconsisting of acetylene, l-propyne, l-butyne, l-pentyne, and3-methyl-1-pentyne in the presence of (3) a freeradial initiatorselected from the group consisting of organic peroxy compounds whichhave half lives in the range of 0.05 to 20 hours at reaction conditions,organic azo compounds which have half lives in the range of 0.05 to 20hours at reaction conditions, and metal alkyls of the metals of Groups11b and Nb of the Periodic System (Mendelyeev) effective for adding saidacetylene to a hydrocarbon group on said aromatic to form a long chainalkenyl aromatic, said contacting being etfected in an inert reactiondiluent at a temperature in the range 150 to 700 F. with a mole ratio of(2) to (3) ranging from 100:1 to 1:1.

6. A process for the production of 3-phenylbutane-l which comprisescontacting ethylbenzene with acetylene at a temperature ranging from 150to about 700 F. in the presence of tetraethyllead as the free radialinitiator.

7. A process for the production of 3-phenylbutene-1 which comprisescontacting ethylbenzene with acetylene at a temperature ranging fromabout 200 to about 650 F. in the presence of tetraethyllead, the moleratio of acetylene to tetraethyllead ranging from about 100:1 to about1:1 and the mole ratio of ethylbenzene to acetylene ranging from about100:1 to about 2:1, and recovering said phenylbutene thus formed asproduct.

8. A process for the production of alkenyl aromatic hydrocarbons whichcomprises contacting under reaction conditions a hydrocarbon-substitutedaromatic hydrocarbon of the formula Ar-CH -R wherein R is selected fromthe group consisting of hydrogen and saturated hydrocarbon radicalsselected from the group consisting of saturated aliphatic, saturatedcycloaliphatic and aromatic radicals of 1 to 10, inclusive, carbonatoms, and Ar is an 7 aromatic nucleus selected from the groupconsisting of alkyl-substituted and unsubstituted monoand polycyclicaromatic hydrocarbon nuclei, said hydrocarbon-substituted aromatichydrocarbon containing from 7 to 24, inclusive, total carbon atoms, withat least one acetylenic material selected from the group consisting ofacetylene, l-propyne, l-butyne, l-pentyne, and 3-methyl-1-pentyne in thepresence of an effective initiating amount of a free radical initiatorcomprising organic peroxy compounds which have half lives in the rangeof 0.05 to 20 hours at reaction conditions including a temperatureranging from about 150 to about 700 F.

9. A process for the production of alkenyl aromatic hydrocarbons whichcomprises contacting under reaction conditions a hydrocarbon-substitutedaromatic hydrocarbon of the formula Ar--CH R wherein R is selected fromthe group consisting of hydrogen and saturated hydrocarbon r-adicalsselected from the group consisting of saturated aliphatic, saturatedcycloaliphatic and aromatic radicals of 1 to 10, inclusive, carbonatoms, and Ar is an aromatic nucleus selected from the group consistingof alkyl-substituted and unsubstituted monoand polycyclic aromatichydrocarbon nuclei, said hydrocarbon-substituted aromatic hydrocarboncontaining from 7 to 24, inclusive, total carbon atoms, with at leastone acetylenic material selected from the group consisting of acetylene,l-propyne, l-butyne, l-pentyne, and 3-methyl-1-pentyne in the presenceof an elfective initiating amount of a free radical initiator comprisingorganic azo compounds which have half lives in the range of 0.05 to 20hours at reaction conditions including a temperature ranging from about150 to about 700 F.

10. A process for the production of alkenyl aromatic hydrocarbons whichcomprises contacting under reaction conditions including a temperatureranging from about 150 to about 700 F. a hydrocarbon-substitutedaromatic hydrocarbon of the formula ArCH R wherein R is selected fromthe group consisting of hydrogen and saturated hydrocarbon radicalsselected from the group consisting of saturated aliphatic, saturatedcycloaliphatic and aromatic radicals of 1 to 10, inclusive, carbonatoms, and Ar is an aromatic nucleus selected from the group consistingof alkyl-substituted and unsubstituted monoand polycyclic aromatichydrocarbon nuclei, said hydrocarbon-substituted aromatic hydrocarboncontaining from 7 to 24, inclusive, total carbon atoms, with at leastone acetylenic material selected from the group consisting of acetylene,l-propyne, l-butyne, l-pentyne, and B-methyll-pentyne in the presence ofan eifective initiating amount of a free radical initiator comprisingactinic radiation,

8 the total dosage to the reaction mixture being in the range of 10 to10 roentgens.

11. A process for the production of alkenyl aromatic hydrocarbons whichcomprises contacting under reaction conditions including a temperatureranging from about to about 700 F. a hydrocarbon-substituted aromatichydrocarbon of the formula AICH2R wherein R is selected from the groupconsisting of hydrogen and saturated hydrocarbon radicals selected fromthe group consisting of saturated aliphatic, saturated cycloaliphaticand aromatic radicals of 1 to 10, inclusive, carbon atoms and Ar is anaromatic nucleus selected from the group consisting of alkyl-substitutedand unsubstituted monoand polycyclic aromatic hydrocarbon nuclei, saidhydrocarbon-substituted aromatic hydrocarbon containing from 7 to 24,inclusive, total carbon atoms, with at least one acetylenic materialselected from the group consisting of acetylene, l-propyne, l-butyne,l-pentyne, and 3-mehtyll-pentyne in the presence of an eifectiveinitiating amount of a free radical initiator comprising gammaradiation, the total dosage to the reaction mixture being in the rangeof 10 to 10 roentgens.

12. A process for the production of alkenyl aromatic rydrocarbons whichcomprises contacting under reaction conditions including a temperatureranging from about 150 to about 700 F. a hydrocarbon-substitutedaromatic hydrocarbon of the formula ArCH -R wherein R is selected fromthe group consisting of hydrogen and saturated hydrocarbon radicalsselected from the group consisting of saturated aliphatic, saturatedcycloaliphatic and aromatic radicals of 1 to 10, inclusive, carbonatoms, and Ar is an aromatic nucleus selected from the group consistingof alkyl-substituted and unsubstituted monoand polycyclic aromatichydrocarbon nuclei, said hydrocarbon-substituted aromatic hydrocarboncontaining from 7 to 24, inclusive, total carbon atoms, with at leastone acetylenic material selected from the group consisting of acetylene,l-propyne, l-butyne, l-pentyne, and 3-methyll-pentyne in the presence ofan eifective initiating amount of a free radical initiator comprisingmetal alkyls of the metals of Groups IIb and Nb of the Periodic System(Mendelyeev) wherein the alkyl groups contain from 1 to 5, inclusive,carbon atoms.

References Cited by the Examiner UNITED STATES PATENTS 2,660,610 11/53Erchak 260668 2,758,140 8/56 Ipatieff et al 260668 2,867,673 1/59Chenicek et a1 260668 3,051,766 8/62 Hunter et a1 260-668 ALPHONSO D.SULLIVAN, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,209,043 September 28, 1965 Norbert Fr Cywinski et al.,

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

Column 5, line 69, for "acetyenic" read acetylenic column 6, line 56,for "3-pheny1butane-l" read 3-ph'enylbutene-l column 8, line 18, for"3-mehtyl" read 3- methylline 24, for "rydrocarbons" read M hydrocarbonsSigned and sealed this 21st day of June 1966 (SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attcsting Officer Commissioner ofPatents

1. A PROCESS FOR THE PRODUCTION OF ALKENYL AROMATICS WHICH COMPRISESCONTACTING AT ELEVATED TEMPERATURES A METHYL-SUBSTITUTED AROMATICHYDROCARBON WHEREIN THE AROMATIC HYDROCARBON IS SELECTED FROMALKYL-SUBSTITUTED AND UNSUBSTITUTED MONO- AND POLYCYCLIC AROMATICHYDROCARBONS, SAID METHYL-SUBSTITUTED AROMATIC HYDROCARBON CONTAININGFROM 7 TO 24, INCLUSIVE, TOTAL CARBON ATOMS WITH AT LEAST ONE ACETYENICMATERIAL SELECTED FROM THE GROUP CONSISTING OF ACETYLENE, 1-PROPYNE,1-BUTYNE, 1PENTYNE, AND 3-METHYL-1-PENTYNE, IN THE PRESENCE OF ACHEMICAL FREE RADICAL INITIATOR SELECTED FROM THE GROUP CONSISTING OFORGANIC PEROXY COMPOUNDS WHICH HAVE HALF LIVES IN THE RANGE OF 0.05 TO20 HOURS AT REACTION CONDITIONS, ORGANIC AZO COMPOUNDS WHICH HAVE HALFLIVES IN THE RANGE OF 0.05 TO 20 HOURS AT REACTION CONDITIONS, AND METALALKYLS OF THE METALS OF GROUPS IIB AND IVB OF THE PERIODIC SYSTEM(MENDELYEEV), AND RECOVERING SAID ALKENYL AROMATIC THUS PRODUCED.